code: def test_smallest_biggest():
      node = RootNode(tree_conf)
  
      with pytest.raises(IndexError):
          node.pop_smallest()
  
      r42, r43 = Reference(tree_conf, 42, 1, 2), Reference(
          tree_conf, 43, 2, 3
      )
      node.insert_entry(r43)
      node.insert_entry(r42)
  
      # Smallest
      assert node.smallest_entry == r42
      assert node.smallest_key == 42
  
      # Biggest
      assert node.biggest_entry == r43
      assert node.biggest_key == 43
  
      assert node.pop_smallest() == r42
      assert node.entries == [r43]
  
file_path: bplustree/tests/test_node.py
imports: import pytest
  from bplustree.const import TreeConf, ENDIAN
  from bplustree.entry import Record, Reference, OpaqueData
  from bplustree.node import Node, LonelyRootNode, RootNode, InternalNode, LeafNode, FreelistNode, OverflowNode
  from bplustree.serializer import IntSerializer
label_desc: Use image node_id 9 for calling a global function with example usage: test_smallest_biggest() without return types